<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>响应式网页</title>
    <link rel="stylesheet" href="css/css.css">
</head>
<body>
    <div class="container">
        <div class="col">网页的左侧</div>
        <div class="col">网页的中间</div>
        <div class="col">网页的右侧</div>
    </div>
</body>
</html>